Modular geomatic pole support system

ABSTRACT

Supports for geomatic equipment, and in particular geomatic poles, can come in the form of bipods and tripods. The support system can be selectively configured as a bipod support and as a tripod support. No modification needs to be made to the geomatic pole, the system is independently capable of configuration. The position of legs of the supports is particularly selected to provide stability in both the bipod and tripod configurations.

BACKGROUND OF THE INVENTION

This invention relates generally to devices which support and holdequipment and more particularly to a foot for such devices suitable forholding geomatic equipment and accessories.

Although the art of surveying is old, recent improvements in equipment,such as automatic electronic total surveying stations, have increasedthe accuracy of the surveying instruments far beyond what was possiblepreviously. Where accepted accuracy for equipment in the not too distantpast was 20 seconds of a degree, accuracy is now commonly required to be1 second of a degree. At these levels of precision, the instruments andmany of their accessories must be supported in a manner which isconsistent and stable. Accordingly, there is a need for closerexamination of support structure used for surveying equipment so thatimprovements in instrumentation will not be lessened by inadequatesupports. Further, the cost of surveying equipment makes it highlyundesirable to damage it by failure of the supports because ofinstability.

Pole supports used in the surveying field typically take the form ofbipods or tripods, but conceivably any number of legs could be provided.Conventionally, it has been necessary to provide completely separateinventories of bipods and tripods to meet the needs of differentcustomers and for different applications. Legs of these supports areusually freely pivotable about a head of the support to swing towardeach other for ease of carrying the support when not in use. A supporthaving three or more legs can support equipment or other items above andout of contact with the ground. Typically, bipods are used to supportsurveying equipment such as a surveying pole, which also contacts theground, but tripods may also be used to support surveying poles. Thestability of such supports can be compromised in situations where thereare forces (e.g., wind and loads from the surveying equipment) acting onthe support and tending to tip the support over. In that case, one ofthe legs is subjected to an upward force component tending to raise theleg up as the support pivots about a point(s) of contact of the otherleg(s) with the ground.

Presently, there is little or no resistance provided by the legs to suchupward forces other than the weight of the leg. Even if there are stakesassociated with the legs that penetrate the ground, the upward forcetends to be directed right along the long axis of the stakes so thatthey are lifted out of the ground. The problem is compounded by the factthat the legs conventionally are mounted for pivoting freely about ahorizontal axis. Even if the support does not tip over, if one leg losescontact with the ground or the frictional resistance to pivotingmovement of the leg becomes sufficiently small, the leg will swing intoward the center of the support. The support is unlikely to regainstability when this happens. Should the support move back toward itsoriginal position, the leg having pivoted inwardly is no longer inposition to engage the ground in a stable position. The center ofgravity of the combined support and surveying equipment may lie outwardof the point where the leg re-contacts the ground so that the entireunit topples over in the opposite direction from the initial tippingmovement. Alternatively as the leg pivots inwardly, the weight of theleg exerts a smaller torque resisting the tipping motion so that themotion may continue causing the unit to collapse. If instability of thesupport causes it to move, even where it does not fall over, accuracy iscompromised.

Although the present invention has particular application for use insupporting surveying and geographic positioning equipment, it is notlimited to such applications. As used herein “geomatic” is intended toencompass surveying and geographic positioning. The invention isenvisioned as being useful to support equipment and other items havingno relation to surveying or geographic positioning.

SUMMARY OF THE INVENTION

Generally, a support system for supporting a geomatic pole comprisesfirst, second and third legs each having mounting structure forconnection to the geomatic pole. The first and second legs are capableof connection to the geomatic pole independently of the third leg fortwo point support of the geomatic pole, and the third leg is capable ofconnection to the geomatic pole with the first and second legs for threepoint support of the geomatic pole.

In another aspect of the present invention, a support system forsupporting a geomatic pole comprises a head including a first headelement and a second head element, and first and second legs mounted onthe first head element. The first head element is formed for releasableconnection to the geomatic pole for two point support of the geomaticpole. A third leg is mounted on the second head element. The second headelement is formed for releasable connection separate from the connectionof the first head element for use in conjunction with said first andsecond legs and first head element for three point support of thegeomatic pole.

The objects and features of the present invention will be in partapparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of a bipod support holding a surveying pole inan upright position on a plot of ground;

FIG. 2 is a side elevation of the bipod support and surveying pole;

FIG. 2A is an enlarged, fragmentary elevation of the bipod support,showing a foot of the bipod support embedded in the ground;

FIG. 3 is an enlarged fragmentary elevation of a lower end of a leg ofthe bipod showing a foot thereof;

FIG. 4 is a section taken in the plane including line 4-4 of FIG. 3;

FIG. 5 is a perspective of the foot as viewed from a vantage interior ofthe bipod support;

FIG. 6 is a perspective of the foot as viewed from a vantage exterior ofthe bipod support;

FIG. 7 is an interior perspective of another form of the foot;

FIG. 8 is a longitudinal section of the foot and leg portion of FIG. 9;

FIG. 9 is a fragmentary exterior perspective of the foot and a portionof the leg with a leg weight exploded therefrom;

FIG. 10 is the perspective of FIG. 9 but showing the weight as connectedto the foot;

FIG. 11 is an exterior perspective of a foot having a stake attachedthereto;

FIG. 12 is a fragmentary perspective of a bipod support leg includingthe foot of FIG. 11;

FIG. 13 is an enlarged, fragmentary perspective of the bipod support andsurveying pole of FIG. 1 showing a connection of the bipod support tothe surveying pole;

FIG. 14 is a fragmentary perspective of the bipod support showing a headof the support partially exploded;

FIG. 15 is an enlarged perspective of a front wall of the head showingan inner surface thereof;

FIG. 16 is an enlarged perspective of the front wall of the head showingan outer surface thereof;

FIG. 17 is an enlarged perspective of a rotary actuator of the head;

FIG. 17A is a fragmentary side elevation of the rotary actuator with aportion broken away to show a ramp at the bottom of a slot on theunderside of the rotary actuator;

FIG. 18 is an elevation of the head with the rotary actuators removedand showing a fragmentary portion of one leg as received in the head forhinged connection therein;

FIG. 19 is an elevation of the bipod support and a surveying pole in acollapsed position and illustrating a line of sight to a bottom point ofthe surveying pole;

FIG. 20 is an enlarged, fragmentary perspective of the support and poleof FIG. 19;

FIG. 21 is a further enlarged perspective of a leg retainer of thesurveying pole;

FIG. 22 is a fragmentary perspective of an upper end of the bipodsupport from a vantage above the support;

FIG. 23 is a fragmentary perspective of an upper end of the bipodsupport from a vantage below the support;

FIG. 24 is a top plan view of the bipod support and a surveying pole;

FIG. 25 is a perspective of a tripod support, a surveying pole andaccessories;

FIG. 26 is an enlarged fragmentary perspective of an upper end of thetripod support, surveying pole and accessories;

FIG. 27 is a top plan view of the tripod support and the surveying polewith accessories removed;

FIG. 28 is an enlarged fragmentary perspective of a joint of a supportleg;

FIG. 29 is the perspective of FIG. 28 with a first leg section of theleg exploded from a second leg section;

FIG. 30 is a section taken in the plane including line 30-30 of FIG. 28;

FIG. 31 is an exploded perspective of an extension locking device of theleg;

FIG. 31A is an enlarged, fragmentary vertical section of lock membersand a wedge of the locking device illustrating the construction ofresilient members of the locking device;

FIG. 32 is a section like FIG. 30 but with parts removed to showadditional details of construction;

FIGS. 32A and 32B are enlarged, fragmentary sections of the lockingdevices illustrating both locked and unlocked positions;

FIG. 33 is a schematic section of the locking device in a lock position;

FIG. 34 is a schematic section of the locking device in an unlockposition;

FIG. 35 is a fragmentary perspective of a surveying pole having amodular mounting system of the present invention;

FIG. 36 is a perspective of a modular mount of a first embodiment;

FIG. 37 is a perspective of a modular mount, partially exploded, of asecond embodiment;

FIG. 38 is a perspective of a modular mount of a third embodiment;

FIG. 38A is an exploded perspective of the modular mount of FIG. 38;

FIG. 38B is an exploded perspective of a modular mount of a fourthembodiment;

FIG. 38C is an exploded perspective of a modular mount of a fifthembodiment;

FIG. 39 is a longitudinal section of the modular mount of FIG. 38 withcompression nuts thereof exploded from a tubular mount body;

FIG. 40 is a perspective of a tripod support and surveying pole withaccessories mounted thereon;

FIG. 41 is an enlarged, fragmentary perspective of a surveying polehaving a modular mount thereon illustrating attachment of four items atone level;

FIG. 42 is a perspective of a modified mount for adjustable support ofan article from generally as seen from the rear of the article;

FIG. 43 is an exploded perspective of the modified mount and article ofFIG. 42;

FIG. 44 is an exploded perspective like FIG. 43, but from a frontvantage;

FIG. 45 is a perspective of a mount having a clipped on adjustablesupport;

FIG. 46 is an elevation of the mount of FIG. 45;

FIG. 47 is a perspective of two components of a connection system of thepresent invention;

FIG. 48 is a perspective of the components of FIG. 47 in an engagedposition from a vantage generally opposite to that of FIG. 47;

FIG. 49 is a side elevation of the connected components of FIG. 48;

FIG. 50 is a perspective of a first modified version of one connectorcomponent of the system;

FIG. 51 is a perspective of a second modified version of a secondmodified version of the one connector component of the system;

FIG. 52 is a perspective of a mount having an adjustable support of asecond embodiment supporting an article;

FIG. 53 is a perspective of the mount and article of FIG. 52, partiallyexploded;

FIG. 54 is a perspective of the mount of FIG. 52 wherein the adjustablesupport is clipped onto a mount body;

FIG. 55 is a fragmentary perspective of a leg including a modified footassembly;

FIG. 56 the perspective of FIG. 55 with parts exploded;

FIG. 57 is a section taken in the plane including line 57-57 of FIG. 58,a screw of the foot assembly not being sectioned and being shown in aretracted position;

FIG. 58 is an inside elevation of the leg and foot assembly;

FIG. 59 is a section taken in the plane including line 59-59 of FIG. 60,the screw 357 being in a fully extended position;

FIG. 60 is an inside elevation of the leg and foot assembly;

FIG. 61 is a an outside elevation of the foot on soil;

FIG. 62 is a outside elevation of the foot on concrete;

FIG. 63 is a bottom plan view of the foot.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and in particular to FIGS. 1 and 2, asupport of the present invention is shown in the form of a bipod support1 holding a surveying pole 3 in an upright position on a plot of groundG (the numbers designated their subjects generally). The pole 3 isextensible and retractable and includes an upper section 5 and a lowersection 7 telescopingly receiving the upper section. The upper and lowerpole sections 5, 7 are held in a selected position of extension by aclamp 9 located at the joint of the upper and lower pole sections.Typically, the upper section 5 has indicia (not shown) indicating theheight above the ground. A pointed tip 11 is mounted on the lower end ofthe lower pole section 7 and engages the ground G. A level 13 mounted onthe lower pole section 7 is used to position the surveying pole 3vertically upright. In the illustrated embodiment, a prism 15 at the topof the pole 3 is used to sight or determine positions with laser,modulated infrared, angular and/or GPS position locators or the like.The prism 15 reflects light back to the position locator forestablishing the location of the prism in a survey. However, it is to beunderstood that other items could be located at the top of the polewithout departing from the scope of the present invention. Reference ismade to co-assigned U.S. application Ser. No. 09/648,172, filed Aug. 25,2000 (the disclosure of which is incorporated herein by reference),showing and describing a surveying pole of the same general type as thepresent invention.

The bipod support 1 includes a head 17 connected to the surveying pole3, a first leg 19 and a second leg 21 (the reference numbers designatingtheir subjects generally). The first and second legs 19, 21 are mountedon the head 17 for pivoting inwardly and outwardly with respect to thehead about a generally horizontal pivot axis. Each leg (19 and 21)includes a first section 23 telescopingly received in a second section25 so that the leg can be selectively increased or decreased in length.The operation of the leg (19 or 21) to extend and retract will bedescribed in more detail hereinafter. Each leg (19 and 21) furtherincludes a foot (generally indicated at 27) at its free end (oppositethe head 17) which engages the ground G. The foot 27 is capable ofpenetrating the ground G to facilitate positive location of the ends ofthe first and second legs. A ground penetrating portion (generallyindicated at 29) of each foot 27 penetrates the ground G and is obscuredfrom view by the ground in FIG. 1. In FIG. 2, the ground penetratingportion 29 of the foot 27 of leg 19 may be seen under the ground.

A description of the foot 27 will be made with reference to the leg 19,the foot on the other leg 21 being of the same construction andarrangement. Referring now to FIGS. 2A, 3, 5 and 6, each foot 27 isshown to include a sleeve 31 receiving an end portion of the leg 19. Theground penetrating portion 29 extends from one side of the sleeve 31 inan inward direction (generally toward the head 17 and surveying pole 3)and a pedal 33 extends from the opposite side. A mount generallyindicated at 35 and located at the top of the sleeve may be used toattach an article (not shown) to the foot 27. The mount 35 is undercuton both sides, leaving laterally projecting lips 37 for use in a tonguein groove type connection which is the same as will be described morefully below. The word “undercut” is used to herein to describe the finalshape of the mount 35, not the method for forming the mount, which in apreferred embodiment would be molded with the other parts of the foot27. Holes 39 extending through the mount 35 in the undercut portion canbe used for bolting an article to the foot 27. In the illustratedembodiment, the ground penetrating portion 29, sleeve 31, pedal 33 andmount 35 are formed as one piece from a suitable polymeric material.However, it is to be understood that the foot 27 may be formed inmultiple pieces and from other materials (e.g., metal) without departingfrom the scope of the present invention.

The ground penetrating portion 29 has a tip 41 which, as can be seen inFIG. 2A, is located inward and under the leg 19 when penetrating theground G. In the illustrated embodiment, the entire ground penetratingportion 29 occupies this position with earth located above the groundpenetrating portion and between the portion and the leg 19. Therefore,support 1 resists forces in both directions along the length of the leg19 to maintain stability of the support. Forces applied downwardly alongthe leg 19 are resisted by the rigidity of the leg and engagement of thefoot 27 with the ground G. Upwardly directed forces along the leg 19 areresisted by the ground penetrating portion 29. Upwardly directed forcesmight occur if the bipod support 1 and surveying pole 3 were subject toa force tending to tip them to the right as shown in FIG. 2. The weightof the earth above the first wall 43 of the ground penetrating portion29 holds the foot 27 in place against such upward movement. The groundpenetrating portion 29 is particularly constructed to facilitateretention, and also initial penetration of the ground G. Moreparticularly, the ground penetrating portion 29 comprises a first wall43 and a second wall 45 intersecting the first wall generally at rightangles so that the ground penetrating portion has a generally “T” shapein cross section (see FIG. 4). The first wall 43 tapers from its widestdimension near the sleeve to the tip 41, roughly in the shape of aspade. The angle made by the first wall 43 relative to the centerline Cof the leg 19 (and sleeve 31) preferably about 90° (i.e., perpendicular)to about 150°. As illustrated in FIG. 3, the angle of the first wall 43is about 120°.

The second wall 45 acts as a gusset to strengthen the ground penetratingportion 29 without substantially increasing the cross section of theground penetrating portion presented to the ground G when the foot 27 ispushed into the ground. The second wall 45 has a roughly triangularshape, tapering toward the tip 41. Thus, it may be seen that the groundpenetrating portion 29 is shaped to facilitate penetration of theground. Retention of the ground penetrating portion 29 is facilitated bybarbs 47 formed in the first and second walls which extend in atransverse direction across the first wall 43, and continue along thesecond wall 45 on both sides thereof. The barbs 47 have the crosssectional shape of an arrow pointed toward the tip 41 of the groundpenetrating portion 29. As the ground penetrating portion is pushed intothe ground G, the leading edges of the barbs 47 facilitate pushing theearth aside to allow the ground penetrating portion 29 to pass into theground. However as each barb 47 passes through the earth and in itsfinal position of penetration, earth moves behind a wide end 48 of thebarb and tends to block movement of the ground penetrating portion 29out of the ground G in the opposite direction. A similar effect occurswhen the shoulders 49 of the first wall 43 immediately adjacent the foot27 pass into the ground. Earth can cover the projecting ends 49 furtherto resist extraction of the ground penetrating portion 29.

Referring to FIGS. 3, 5 and 6, it may be seen that the pedal 33 includesa foot pad 51 projecting outwardly from the sleeve 31 to an outer wall53 extending at an angle to the foot pad and generally in plane with thefirst wall 43 of the ground penetrating portion 29. A bridge wall 55extends between the sleeve 31, foot pad 51 and outer wall 53 andconnects the three to form a rigid structure having a low weight andemploying minimal material. A hole 57 in the bridge wall 55 can be usedto connect items (not shown) to the foot 27. The foot pad 51 includes afoot engagement surface having grooves 59 to enhance traction on thesurface. The angle the foot pad 51 makes with the center line C of thesleeve 31 (and hence the leg 19) is selected to that at least asubstantial component of a force applied by pressing down on the footpad 51 is directed along the first wall 43 of the ground penetratingportion 29 toward the tip 41. In a preferred embodiment, the foot pad 51makes an angle with the center line C of the sleeve 31 which is greaterthan or equal to about 100°.

Modified versions of the foot 27 shown in FIG. 7, FIGS. 8-11 and FIG. 12are designated generally at 27A, 27B and 27C, respectively.Corresponding parts of the modified feet 27A, 27B, 27C are indicated bythe same reference numbers used for parts of the foot 27, but with afollowing alphabetic identifier. Like the version of the foot 27 shownin FIGS. 1-6 the modified versions of the foot 27A, 27B, 27C eachincludes a sleeve (31A, 31B) which receives a lower end portion of theleg 19. As shown in FIG. 8, a lower end 61 of the leg 19 is receivedalmost to the bottom of the sleeve 31B and at least a portion of theground penetrating portion 29B is directly radially opposite the leg.The foot 27B extends in an axial direction beyond the lower end 61 ofthe leg 19 only a very short distance. Thus, the fully retracted lengthof the leg 19 including the foot 27B having the projecting groundpenetrating portion 29B is not substantially greater than it would bewithout the foot. It will be understood that as the angle of the firstwall 43B of the ground penetrating portion 27B moves more toward 90° tothe center line of the sleeve 31B, the axial extent of the foot 27Bbeyond the lower end 61 of the leg 19 is further reduced.

Referring to FIG. 7, the ground penetrating portion 29A of the foot ismodified by lengthening the barbs 47A on the first and second walls 43A,45A so that they contact each other without intervening flat spacespresent on the ground penetrating portion 29 of FIGS. 1-6. The mount 35Aincludes two identical undercut formations 63A on opposite, outer andinner sides of the sleeve 31A, both of which are capable of sliding,tongue in groove connection to an article (not shown). As shown in FIGS.9 and 10, the presence of two mounting formations 63B allows one or morearticles to be attached to the foot 27B by bolting on opposite sides ofthe foot. In the illustrated embodiment, the article is shown as a legweight having first and second members (designated 65 and 67,respectively) capable of being attached on laterally opposite sides ofthe foot 27B. The second weight member 67 has four smooth holesgenerally in the four corners of the member which receive bolts 69through the second weight member. The bolts 69 pass through the top andbottom holes 39B formed in the undercut portion of the mountingformations 63B and into threaded holes 70 in the second weight member65. As the bolts 69 are tightened down, the first and second weightmembers 65, 67 are clamped against the mounting formations 63B (FIG.10). The weight members 65, 67 are formed so that they receive a portionof the foot and have ridges 71 which are received in the undercutportions of the mounting formations 63B.

The version of the foot 27B shown in FIG. 9 has a foot pad 51B with anundulating (rather than grooved) foot engagement surface. Moreover, thepedal 33B is particularly formed to facilitate a tongue in grooveconnection of an article (not shown). The outer wall 53B of the pedal33B is wider than the foot pad 51B defining a ridge 73B which is opposedby a ridge 75B formed in the bridge wall 55B of the foot. The ridges73B, 75B define a groove used to mount articles on the foot 27B. Thesame arrangement of ridges 73B, 75B is present on the side of the foot27B not seen in FIG. 9. The bridge wall 55B is thicker than the bridgewalls 55, 55A of the FIGS. 5 and 7 embodiments, and does not entirelyclose off the opening between the sleeve 31B, foot pad 51B and outerwall 53B. Three holes 77B are formed in the bridge wall 55B and extendcompletely through the bridge wall.

One example of an article which can be mounted on the foot is a stake 79illustrated in FIG. 11. The stake 79 has a long body 81 with a pointedend projecting substantially beyond the tip 41B of the groundpenetrating portion 29B of the foot 27B when ground conditions demanddeeper penetration to secure the leg 19. Although the stake body 81 isshown with a conventional form, it is contemplated that the stake couldbe barbed and/or have a small cross section (like the T-shaped crosssection of the ground penetrating portion) without departing from thescope of the present invention. A head 83 of the stake 79 is formed witha channel 85 having at its free edges opposed, inwardly projecting lips87 which are slidingly received in the grooves defined by opposed ridges73B, 75B of the foot 27B to connect the stake to the foot. The lips 87have a generally “L” shape in cross section and present a flat surfaceto the bottom of the groove. The flat surfaces each have three holeswhich are in registration with the three holes 77B in the bridge wall.The number of holes may be other than three without departing form thescope of the present invention. Further connection is achieved bypassing bolts 89 through the holes in the lips 87 and bridge wall 55B.The bolts 89 can be secured by nuts (not shown) or by internallythreading the holes in one of the lips 87, or in another suitablemanner.

A modified form of the foot 27B shown in FIG. 9 is shown in FIG. 12 andindicated generally by reference character 27C. The foot 27C has aclosely similar construction to the foot 27B. However, there is no mountcorresponding to mount 35B of FIG. 9. The foot 27C will not be furtherdescribed herein. Parts of the foot 27C corresponding to those of foot27B will be indicated by the same reference number, but with the suffix“C”.

A retainer 91 located at the joint of the first and second leg sections23, 25 releasably retains the lower end of the first leg section 23 inthe second leg section 25. Although not shown, a retainer could beformed with structure for mounting accessories onto the leg 19.Referring to FIGS. 29 and 30 illustrating the leg sections 23, 25 at thejoint, the leg sections are formed to be snapped together and apart asneeded for cleaning, repair or replacement. For example, a second legsection (not shown) having a different foot or mounting structure couldbe attached to the support 1 in place of the second leg section 25. Thelower part of the first leg section 23 has apertures 105 through whichrespective ears 107 project, extending out to the sides of the first legsection. The ears 107 are made of a resiliently deformable material.Deformation or flexing is enhanced by weakening regions around the ears107. As shown in FIG. 31, slots 109 are formed around the ears 107 tofacilitate inward flexing of the ears. In the illustrated embodiment,the ears 107 are formed as part of a locking device described below, andalso function to attach the device to the first leg section 23. It isnot necessary for the ears 107 to be formed as a part of another legstructure to fall within the scope of the present invention. Forinstance, the ears 107 could be formed as a single piece separate fromthe locking device.

When the first leg section 23 is telescopingly received in the secondleg section 25 (as shown in FIG. 30), the ears 107 engage the innersurface of the second leg section, helping to center the first andsecond leg sections and helping to eliminate relative lateral movement(“slop”) between the leg sections. The ears 107 are engageable with arim 111 of the retainer 91 attached at the joint to prevent inadvertentwithdrawal of the first leg section 23 from the second leg section 25.The rim 111 of the retainer 91 extends inwardly from an inner wall ofthe second leg section 25 forming an opening 113 which is about the samesize (or only slightly larger) than the outer dimensions of the firstleg section 23. Thus, because the ears 107 project outwardly from thefirst leg section 23, they cannot fit through the opening 113 withoutdeforming. Alternatively, the ears 107 could be relatively rigid and therim 111 could be deformable, or both the ears and the rim could bedeformable to permit the ears to move past the rim out of the opening.FIG. 30 shows the first leg section 23 fully extended from the secondleg section 25 with the ears 107 engaging the underside of the rim 111preventing further extension of the first leg section. In normaloperation of the bipod support leg 19 the first and second leg sections23, 25 will be prevented from separating by the ears 107. Because theears are deformable, application of sufficient force to the first andsecond leg sections 23, 25 in an axial direction will cause the ears 107to resiliently deform inwardly into the second leg section 25 and allowthe first leg section 23 to snap past the rim 111 and out of the secondleg section 25. Reconnection of the leg sections 23, 25 can be made byapplying a force to the leg sections in opposite directions so that theears 107 deform and snap past the rim 111 in the other direction. Theears 107 return to their undeformed condition inside the second legsection 25 to again inhibit inadvertent separation.

The first and second leg sections 23, 25 are also preferably heldagainst rotation relative to each other about the center line C of theleg 19. The first and second leg sections 23, 25 have correspondingcross sectional shapes which are not round so that relative rotation isnot permitted when the leg sections are engaged with each other.Accordingly, the foot 27B is held in position with the groundpenetrating portion 29B projecting inwardly. In this way, the foot 27Bis prepared to be pushed into the ground G without having to manuallyposition the foot about the axis of the leg 19. However, it isenvisioned that leg sections of round cross section (not shown) could beused. In that event, the foot pad of the pedal is preferably formedsubstantially wider and with traction features (not shown) arranged toenhance traction both lengthwise and widthwise of the foot pad so thatit is possible using one's foot to position the ground penetratingportion about the center line of the leg before pushing it into theground G.

Another feature of the present invention can work in conjunction withthe foot (27, 27A, 27B, 27C) of the present invention to increasestability of the bipod support 1. More particularly, and with referenceto FIGS. 13-18, each leg 19, 21 can be locked by hinge locks (generallyindicated at 115) against pivoting angularly with respect to the head 17to prevent the leg from swinging inward if the leg momentarily losesgripping engagement with the ground G. Thus, the weight of the leg (19or 21) is always maximally applied to resist tipping of the bipodsupport 1 and surveying pole 3 in a direction which would cause the legto lift off the ground. It will be understood that this feature, whileuseful independently, acts beneficially in conjunction with the grippingaction of the ground penetrating portion (29, 29A, 29B, 29C) of the foot(27, 27A, 27B, 27C) to resist such tipping motion.

The head 17 has one of the hinge locks 115 for each leg to lock the legin a fixed angular position relative to the head. Referring generally toFIGS. 13 and 14, the head 17 comprises a top wall 117, a bottom wall119, a back (or “first”) wall 121 and a front (or “second”) wall 123which are connected together to form a box structure. The back wall 121is formed by three generally planar members, including outer members 125arranged at angles to a center member 127 for setting the angle ofseparation of the legs 19, 21. A roughly triangular brace 129 connectedto the center member 127 strengthens the head 17 and provides a locationfor securing the top and bottom walls 117, 119 to the back wall 121. Theouter members 125 each have tangs 131 two of which project upward froman upper edge of the member and two of which project downward from alower edge of the member (all four of the tangs 131 of only one of theouter members may be seen in FIG. 14). The front wall 123 has two outermembers 133 and a thin center member 135. The outer members 133 of thefront wall 123 also have tangs 137 projecting upwardly from their upperedges and projecting downward from their lower edges. The top wall 117and bottom wall 119 each have angled outer members 139 and a pie-shapedcenter member 141. The interior faces of the top and bottom walls 117,119 are formed with channels 143 along their inner edges and channels145 along their outer edges which receive and retain the tangs 131 ofthe back wall 121 and tangs 137 of the front wall 123, respectively. Thetop wall 117, bottom wall 119, back wall 121 and front wall 123 aresecured together by three screws 147 which are received through holes149 in the top wall into threaded holes in the top of the brace 129, andby three screws 151 received through holes 153 in the bottom wall intothreaded holes (not shown) in the bottom of the brace. As connectedtogether, the walls 117, 119, 121 and 123 form a box giving the head 17strength.

A large diameter hinge pin 155 projects forward from each of the outermembers 125 of the back wall 121. The hinge pin 155 provides arelatively large cylindrical surface on which the leg 19 may pivot. Forexample the diameter of the hinge pin 155 may be 1½ inches and thelength of the hinge pin may be 1 7/16 inches. A cap 157 mounted on anupper end of the head 17 of each leg 19, 21 is joined to a tubularsleeve 159 sized to slide onto the hinge pin 155 in close fittingrelation. The tubular sleeves 159 (and hence the legs 19, 21) arecapable of free pivoting motion on their respective hinge pins 155. Thesleeves 159 are retained on the hinge pins 155 by the back wall 121 andthe front wall 123 of the head 17.

Referring particularly to FIG. 14, the hinge lock 115 includes firstdetents associated with the head 17 and second detents associated withthe leg (19 or 21). Only one of the hinge locks 115 of the bipod support1 will be described, the other being identical. The first detentscomprise a set of detents 163 formed on the interior surface of theouter member 133 of the front wall 123 and extending around an opening165 in the front wall (FIG. 15). The second detents include a set ofdetents 167 on each of the axially facing ends of the sleeve 159. Thedetents in each of the sets 163, 167 are in the form of ridges 169 (seeFIG. 15) extending generally radially of the pivot axis of the leg 19.The ridges 169 are spaced apart a distance slightly more than the widthof each ridge so that a ridge of one set of detents 163, 167 may fitbetween adjacent ridges of another set. Collectively, the ridges 169give each of the detent sets a serrated appearance. The set 167 ofsecond detents on one side of the sleeve 159 opposes the back wall 121of the head 17, and the set 167 of second detents on the opposite end ofthe sleeve opposes the set 163 of first detents on the front wall 123.The opposing sets of detents (167 and 163) can be brought intoengagement so that the detents mesh with each other, preventing rotationof the sleeve 159 relative to the back and front walls 121, 123 of thehead 17 and locking the leg 19 in place.

Meshing and releasing of the detents 169 is permitted because the frontwall 123 is capable of moving to change the distance between theopposing outer members 125, 133 of the back and front walls 121, 123.FIG. 18 illustrates the head 17 and a sectioned portion of the sleeve159 received on the hinge pin 155. The width of the back wall tang 131received in the channels 143 of the top and bottom walls 117, 119 issubstantially identical to the width of the channels so that the backwall 121 is held against movement toward or away from the front wall123. However, the tangs 137 of the front wall 123 and the front wallitself are thinner than the width of the channels 145 in the top andbottom walls 117, 119 receiving those tangs. As a result, the front wall123 may move toward and away from the back wall 121. Movement of theouter member 133 of the front wall 123 away from the outer member 125 ofthe back wall 121 causes the opposing sets of detents (167 and 163) torelease from each other, permitting the leg 19 to pivot freely on thehinge pin 155. This is the position illustrated in FIG. 18. Movement ofthe outer member 133 of the front wall 123 toward the outer member 125of the back wall 121 meshes the opposing detent sets, locking the leg 19in a selected angular position.

To selectively mesh and release the opposing sets of detents, a handle171 (broadly, “actuator”) is provided which is mounted on an end of thehinge pin 155 by a screw 173 and washer 175 for rotation about the pivotaxis of the leg 19. As shown in FIG. 17, the handle 171 further includesa tubular spindle 174 having axially extending channels 174A on itsexterior surface. The spindle 174 is received through the front wallopening 165 into an axial passage 177 of the hinge pin 155 and into abearing 176 (see FIG. 18) rotatably mounted inside the axial opening177. The bearing 176 has axially extending bungs 178 which are receivedin the channels 174A of the spindle 174 and have a releasable,interference fit with the spindle so that the bearing turns with thespindle. The screw 173 passes through the front wall opening 165, out ofthe spindle 174, through the bearing 178 into a threaded hole (notshown) at a closed end of the axial passage 177 opposite the open end. Afinger grip 179 extending outwardly from a round central portion 181 ofthe handle 171 facilitates gripping the handle to turn it (FIG. 17).

Referring to FIG. 16, the front wall 123 is formed with tabs 183. Threetabs are spaced around each of the openings 165 in the front wall 123and project forward from the front wall. The tabs 183 are received inrespective arcuate slots 185 on the underside of the handle 171 (seeFIG. 17). The bottom of the slots 185 are formed as arcuate ramps 187,as may be seen in FIG. 17A. Thus, the slots 185 are shallower at one endand deeper at the opposite end. As mounted on the hinge pin 155, thetabs 183 engage and ride on the arcuate ramps 187 in the slots 185 ofthe handle 171. One of the tabs 183 as received in the slot intoengagement with the ramp 187 is illustrated in phantom in FIG. 17A. Inthe position of the handle 171 shown in FIGS. 13 and 14, the tabs 183are in the deepest part of the slots 185. In this position, the frontwall 123 is allowed to move away from the back wall 121 releasing theopposing detents (167 and 163) from their meshing engagement. Thus, thelocking device is unlocked and the leg 19 may be pivoted freely. Turningthe finger grip 179 of the handle 171 downward, causes the tabs 183 toslide up the arcuate ramp 187 to a shallow portion of the slot. Thehandle 171 is fixed by the screw 173 from movement along the pivot axisof the leg 19 toward or away from the back wall 121, so the outer member133 of the front wall 123 is pushed toward the outer member 125 of theback wall, enmeshing the opposing sets of detents (167 and 163). Thus,it may be seen that the legs 19, 21 are locked and unlocked with a smallturn of the handle 171. Other constructions for producing movement ofthe front wall 123 may be employed without departing from the scope ofthe present invention. For instance, a handle and front wall may beformed with interengaging ramps (not shown).

Use of the bipod support 1 as attached to the surveying pole 3 isfurther facilitated by a leg retainer 191 mounted on the lower polesection 7 of the surveying pole, as illustrated in FIGS. 19-21. The legretainer 191 comprises a ring 193 which is capable of being attached tothe surveying pole 3 such as by gluing, or in a less permanent fashion.A shelf 195 projecting outwardly from the ring 193 is enclosed by thering and a retaining wall 197 extending around the peripheral edge ofthe shelf and projecting upwardly therefrom. The leg retainer 191 ismounted on the pole 3 so that the shelf 195 extends outwardly from thepole on the opposite side of the pole from the head 17 of the bipodsupport 1. In a stowed position of the bipod legs 19, 21, the legs areretracted and the tips 41 of the ground penetrating portions 29 arereceived on the shelf 195 within the retaining wall 197 so that the feet27 are held in place by the leg retainer 191. To place the tip 41 of theground penetrating portion 29 of one leg (e.g., leg 19), the leg isfirst retracted to a length where the tip is higher than the retainingwall 197 of the leg retainer 191. The leg 19 is pivoted so that the tip41 is over the shelf 195, and the leg is extended to bring the tip intoengagement with the shelf within the retaining wall 197. The other leg21 is stowed in the same way. The head 17 is preferably made of aresilient polymeric material. The position of the legs 19, 21 as stoweddeparts somewhat from the pivot path of the legs allowed by the hingepin 155. Accordingly, the head 17 and/or legs 19, 21 are slightlyresiliently deflected in the stowed position. In another version of thebipod support (not shown), the leg retainer 191 is omitted and the legs19, 21 are retained in a stowed position (substantially as shown in FIG.19) by locking the hinge locks 115 of each leg.

The bipod support 1 is constructed for quick attachment and release fromthe surveying pole 3. Referring to FIG. 13, the surveying pole 3 isequipped with a mount, generally indicated at 201, affixed to the poleat the upper end of the lower pole section 7. The mount 201 includes twoidentical undercut formations 203 on opposite, outer and inner sides ofthe mount. The formations 203 are both capable of sliding, tongue ingroove connection to an item, such as the bipod support 1. The mount 201will be more fully described hereinafter. Reference is made to FIG. 35,showing the mount 201 on a surveying pole 3 on a larger scale.

The head 17 of the bipod support 1 has a channel 205 defined byopposite, vertically extending walls 207 having lips 209 projectingtoward each other over the channel (see FIGS. 22 and 23). The upper endof the channel 205 is open, but an end wall 211 constituting anextension of the bottom wall 119 of the head 17 closes the lower end ofthe channel. The bipod support 1 is attached to the surveying pole 3 byaligning the grooves on the mounting formation 203 with the lips 209 onthe channel walls 207 of the head 17 and sliding the mounting formationdown into the channel 205 until the mounting formation engages the endwall 211 closing the lower end of the channel. The mounting formation203 is restrained from moving out of the channel 205 by a gate knob 213rotatable about a vertical axis to frictionally engage the uppermounting formation to hold it in place relative to the head 17, and tomove away from the channel to permit the mounting formation to beremoved from or inserted into the channel. The gate knob 213 is mountedfor rotation by a bolt 215 received in a circular base 217 on the topwall 117 of the head 17 (FIG. 14). The bolt 215 is threaded into a nut218 on the underside of the top wall 117 so that the gate knob 213 mayrotate relative to the head 17. Other devices to hold the head 17 on thesurveying pole 3 (not shown) are contemplated. For instance, a lever toactuate the gate knob could be located remotely from the knob, or theknob could also hook the mounting formation in the fashion of a windowlock.

In one preferred embodiment, the bipod support 1 is part of a supportsystem which can be converted from two legged support of the surveyingpole 3 (or other supported item) to a three legged or tripod support.For that reason, the legs 19 and 21 are best arranged so that they arespread apart farther than a conventional bipod. However, a conventionalspacing of the legs 19 and 21 could be used without departing for thescope of the present invention. As shown in FIG. 24, the legs 19, 21 areseparated by an angle of about 105°, but could be arranged at an anglegreater than 90° and less than 120° for use in the support system. Thispositioning facilitates support of the surveying pole 3 both when thebipod support 1 is used by itself and when used with a single legsupport (generally indicated at 221) collectively to form a tripodsupport, as shown in FIG. 27. The angle between a leg 223 of the singleleg support 221 and each of the legs 19, 21 of the bipod support isapproximately 127.5°, providing opposition of the legs 19, 21 and 223 tosupport the surveying pole 3.

In the context of the support system, the head 17 of the bipod support 1constitutes a “head element”. The single leg support 221 includes a headelement 225 having a similar construction to the head element 17 of thebipod support 1, but sized as needed for a single leg 223. The headelements 17, 225 of the bipod support 1 and the single leg support 221collectively constitute a “head” of the support system. The single legsupport 221 is attached to the mount in a manner substantially identicalto the bipod support 1. However, it is to be understood that a singleleg support could be attached to a bipod support which is in turnattached to the pole 3 (not shown). In that event, the leg support wouldstill be considered capable of independent, or separate attachment tothe pole 3, even though the attachment is indirect through the bipodsupport. Moreover, the pivoting connection of the leg 223 to the headelement 225 is the same except for sizing, and will not be furtherdescribed. It is noted that the leg 223 can be releasable locked both ina selected angular position relative to the head element 225 and in aposition of telescoping extension just as described above for leg 19 ofthe bipod support 1. Although the bipod support 1 and the single legsupport 221 are shown, other arrangements are possible. For example, allof the supports in the system could be single leg supports 221, or twobipod supports 1 could be used at the same time. The number of supportsand legs can be other than two or three without departing from the scopeof the present invention. Moreover, the supports 1, 221 could be used tohold an item (not shown) which does not itself contact the ground.

A locking device (generally designated at 228) for locking the first andsecond leg sections 23, 25 in a fixed position of extension (orretraction) is illustrated in FIGS. 28-34. The description of thelocking device 228 will be made with reference to one of the legs 19,the locking devices in the other legs (21, 223) being identical. Thelocking device 228 is configured for easy operation by depressing abutton 229 located at the upper end of the first leg section 23 torelease the locking device, as will be explained more fully. An uppersurface 231 of the button 229 is slanted so that even though the leg 19extends at an angle to vertical, the upper surface faces substantiallyupward for ease of access to press down (see. e.g., FIG. 13). Thisergonomic construction helps the button 229 to be accessible no matteron what side of the support a user is standing.

As shown in FIGS. 33 and 34, the button 229 is connected by a screw 232to a tubular rod 233, which is internally threaded at the top to receivethe screw. The screw 232 is fixed (such as by gluing) to the rod 233 sothat the two are fixed rotationally. The button 229 is secured betweenthe head of the screw 232 and an upper end of the rod 233 so that thebutton, screw and rod move conjointly in translation, but the screw androd are allowed to rotate relative to the button The rod 233 extendsdown through the hollow interior of the first leg section 23, betweenlock members 235 to a wedge 237 connected to the bottom end of the rodbelow the lower end of the head 17. The rod 233 and wedge 237 move withthe button 229 conjointly up and down along the axis of the leg 19. Thelower end of the rod 233 is externally threaded and attached by threadsto the wedge 237. Rotation of the screw 232 rotates the rod 233 and,depending upon the direction of rotation, draws the wedge 237 nearer tothe button 229 or moves it farther away. Two spaced apart bushings 239(FIG. 29) are located in and supported by the first leg section 23. Thebushings 239 receive the rod 233 through them to guide the rod andsupport it against buckling.

As may be seen in FIG. 31, the lock members 235 are opposed to eachother and each have tabs 241 which fit in slots 243 of the opposing lockmember to loosely connect the lock members together. The lock members235 together define two close fitting guide openings 244 in an upperguide portion of the lock members. The guide openings 244 receive therod 233 between the lock members 235 to center the rod and wedge 237 inthe second leg section 25. The lock members 235 each include the ears107, described above, which permit the first and second leg sections 23,25 to be snapped together and apart, but also fix the lock members tothe head 17. Each lock member 235 is generally channel shaped, andincludes lower wall sections 245 having inner edges 247 inclinedrelative to the center line C of the leg. As best seen in FIG. 32, theedges 247 converge toward the center line C from the lower end of thelock members 235 upward. As the wedge 237 is drawn up into the lockmembers 235, the sides of the wedge engage the inclined inner edges 247of the lower wall sections 245 so that the lower ends of the lockmembers are forced apart.

The lock members 235 are also positively drawn together by action of thewedge 237 in the unlock position of the locking device 228. In thatregard, an upward extension of the wedge 237 is formed with undercutcams 248 engageable with respective lock members 235 to pull them towardeach other in the unlock position. Each of the lock members 235 has aroughly channel shaped construction, with the open portion of eachchannel facing the open portion of the opposite lock member channel. Ina mid-section of the lock members 235, ramps 249 project inwardly fromthe sides of the channel toward each other. These ramps 249 are receivedunder the undercut portions of the cams 248 such that they are capturedby the cams. The ramps 249 angle inwardly from the bottom to the top ofthe lock member mid-section. Thus, it will be understood that as thewedge 237 is moved down from the position shown in FIG. 32A bydepressing the button 229, the cams 248 move along the ramps 249 drawingthe lower portions of the lock members toward each other, as shown inFIG. 32B, and away from the inner surface of the second leg section 25.The wedge 237 moves down so that only a thinner portion of the wedgeremains between the lock members 235, allowing the lower portions of thelock members to move toward each other. The action of the cams 248, andcentering of the rod 233 and wedge 237 in the second leg section 25facilitate complete disengagement of the lower portion of the lockingdevice 228 from the second leg section. Thus, the leg section 23, 25slide freely relative to each other and wear on the locking device 228is reduced.

The lock members 235 are configured so that only lower portions of thelock members move under influence of the wedge 237. A hinge 250 isformed at a location of each lock member 235 where sides of the channelare cut away and the remaining wall is thinned (see FIG. 31A). Thus, thelower portion of each lock member 235 may pivot about an axisperpendicular to the longitudinal axis of the leg 19 between the lockand unlock positions. The lower portions are farther away from eachother in the lock position and closer together in the unlock position.An engagement portion of each lock member 235 for engaging the innersurface of the second leg section 25 to grip the second leg section andlock the first leg section 23 in a fixed position of extension relativeto the second leg section is defined by a resilient member (generallyindicated at 251) overmolded onto the lower portion of the lock member.The resilient member 251 is formed of a softer elastomer and has a firstor upper edge 251A and a second or lower edge 251B. The resilient member251 tapers in thickness from its center toward the edges 251A, 251B. Inother words, a thickness T1 at the center of the resilient member 251 isgreater than the thickness T2 at the edges 251A, 251B. It is to beunderstood that the thickness edge 251A, 251B does not have to be thesame. This curvature of the resilient member 251 reduces wear of theresilient member. However, wear can be accommodated by rotating thescrew 232 as mentioned above to move the wedge 237 nearer to the button229 so that the lock members 235 are driven further apart by the wedgein the lock position. The locking device 228 is also capable ofautomatically compensating for wear of the resilient members 251 whichwill occur over time. The inclined inner edges 247 of the lower wallsections 245 and the sides of the wedge 237 interact to drive the lowerportions of the lock member 235 further apart as the resilient members251 wear to assure continued tight gripping of the second leg section 25in the lock position. In other words, the wedge 237 is drawn fartherinto the lock member as the resilient members 251 wear.

In addition, each resilient member 251 has laterally extendingserrations 252 which facilitate both the gripping action of theresilient member with the inner surface of the second leg section 25 andthe release from the second leg section. Gripping is enhanced because inthe lock position any moisture between the resilient member 251 and theinner surface of the second leg section 25 can be channeled to the sidesof the resilient member and out from between the two surfaces so that itdoes not interfere with gripping. Release is facilitated because thesoft elastomer of the resilient member 251 has a tendency to cup andform a vacuum between the resilient member 25 and the inner surface ofthe second wall, making release difficult. The serrations 252 break thevacuum because they communicate air from the side of the resilientmember 251 so that a vacuum is not drawn.

It is envisioned that frictional engagement portions other than theresilient members 251 could be used, such as multiple O-rings (notshown) received around both lock members 235. In that case, the O-ringscould also serve to bias the lock members 235 to the unlock position. Aseparate spring or the like (not shown) could be used to bias the lockmembers 235 toward each other for positive release disconnect in theunlock position. Each lock member 235, including the upper and lowerportions, the ears 107, lower wall sections 245, ramps 249, is molded asone piece from low friction material, such as nylon or another polymer.Molding from one piece eliminates relative movement and possible loss ofalignment between parts of the lock members 235 which otherwise helps toassure complete disengagement of the resilient members 251 from theinner surface of the second leg section 25 in the unlock position. Useof a synthetic material having a low coefficient of friction, such asnylon, allows the ears 107 to freely slide along the interior of thesecond leg section 25. It is to be understood that these could be formedas separate pieces without departing from the scope of the presentinvention.

Having described the construction of the locking device 228, itsoperation to lock and unlock the first and second leg sections 23, 25will now be described with reference to FIGS. 33 and 34. Normally, aspring 257 located above an annular shoulder 259 in the cap 157 of theleg 19 biases the button 229 and rod 233 attached thereto upward (asindicated by the arrow) along the center line C of the leg to the lockposition. Although the spring 257 is located in the cap 157 and isreceived into a passage in the button 229, the spring may be locatedanywhere along the length of the rod 233 without departing from thescope of the present invention. The wedge 237 is drawn into the lockmembers 235 by the spring 257 and the sides of the wedge engage theinclined inner edges 247 of the lower wall sections 245. The lowerportions of the lock members 235 are forced apart (as indicated byarrows) so that the resilient members 251 grippingly engage the innersurface of the second leg section 25 (see also FIG. 32A). In this lockposition, the first and second leg sections 23, 25 are held againsttelescoping movement to extend or retract the leg 19.

To unlock the leg sections 23, 25, the button 229 is depressed (asindicated by the downward arrow in FIG. 34) forcing the button and rod233 down against the bias of the spring 257. The wedge 237 moves downand partially out from between the lock members 235. At the same time,the cams 248 slide down the ramps 249 drawing the lower portions of thelock members 235 together and disengaging the resilient members 251 fromthe inner surface of the second leg section 25 (se also FIG. 32A). Thisaction does not rely on any material retaining its resiliency over aperiod of time as the cams 248 pull the lock members 235 to the unlockposition every time. The guide openings 244 in the upper guide portionof the locking members 235 center the rod 233 and lock members so thatthe resilient members 251 disengage the inner wall of the second legsection 25. The first and second leg sections 23, 25 are free to sliderelative to each other without interference from the locking device 228.

As shown in FIG. 34, a cavity 261 in the cap 157 in which the button 229is received is wider than the button, permitting some side-to-sidemovement of the button within the cavity relative to the cap. A catch263 formed on the cap 157 generally adjacent to the cavity 261 opens onone side toward the button 229. A toe 265 formed on the lower end of thebutton 229 can be inserted into the open side of the catch 263 by movingthe button sideways in its fully depressed position (FIG. 34). The forceof the spring 257 holds the toe 265 in the catch 263 so that the lockingdevice 228 is retained in the unlock position without continuing toapply thumb pressure to the button 229. The toe 265 and underside of thecatch 263 are angled upwardly to enhance retention of the button 229 inthe unlock position. The first and second leg sections 23, 25 are thusfreely movable relative to one another without holding the button 229down. By moving the button 229 sideways away from the catch 263, the toe265 can be removed, and the locking device returned to the lock positionof FIG. 33. The manipulations necessary to engage the button 229 withthe catch 263 to hold it in the unlock position and to release thebutton from the catch can be performed with the thumb of one hand.However, other ways of manipulating the holding the locking device 228in the unlock position may be employed without departing from the scopeof the present invention.

Mounts 35, 35A, 35B, 201 of the present invention have previously beendescribed in association with the foot (27, 27A, 27B), the joint of theleg sections 23, 25 and in the context of mounting the support(s) to thesurveying pole 3. These mounts permit a tongue in groove connection, ora bolted on connection, or both. It to be understood that the mounts donot need to be capable of accepting both bolted and tongue in grooveconnections. Referring to FIG. 35, a first and a third embodiment ofmodular mounts are shown, including the fixed mount 201 and aselectively positionable mount 267A. The mount 201 located at the upperend of the lower pole section 7 was partially described in regard toattachment of the support 1 to the pole 3. Mount 201 includes a tubularbody 269 permanently attached to the surveying pole 3 such as by gluing.The mount 201 is shown separate from the surveying pole 3 in FIG. 36. Itmay be seen that in addition to the mounting formations 203 and boltholes 271, the mount 201 incorporates spaced apart posts 273 whichattach the clamp 9 used to fix the axial position of the upper and lowerpole sections 5, 7. However, such additional structure is not necessaryto the present invention.

A selectively positionable mount 267 (see FIG. 37) of a secondembodiment includes a tubular body 277, mounting formations 279 havingbolt holes 280 like the mount 201 of the first embodiment. However, theinternal diameter of the positionable mount 267 is larger than thediameter of the lower pole section 7 so that the body 277 may slide ontoand along the lower section. The upper end of the tubular body 277 isthreaded and has four axially extending slots 283 which permit thethreaded portions of the body to flex inwardly relative to the remainderof the body 277. A compression nut 285 has a central opening 287 largerthan the diameter of the lower pole section 7. Threads formed internallyof the compression nut 285 are diametrically closer at the top end ofthe nut than at the bottom, thereby forming a wedge. When screwed ontothe upper end of the tubular body 277, the compression nut 285 forcesthe threaded portions to bend inwardly into gripping engagement with thelower pole section 7 to releasably fix the positionable mount 267 on thelower pole section.

The mount 267A constitutes a third embodiment of the mount, and is shownin FIGS. 38, 38A and 39. The mount 267A has threaded portions at bothends of the tubular body 277A and a second compression nut 285A forscrewing onto the lower threaded portion for more secure attachment. Thetubular body 277A of the mount 267A is formed of two semi-cylindricalparts 286A capable of being fitted together. Each body part 286Areceives a circumferential portion of the pole 3. It is to be understoodthat the mount 267A could be formed as a single piece, or in more thantwo parts within the scope of the present invention. As shown, the parts286A are identical to each other. Each body part 286A includes fourtubular projections 288A which can be received in openings 280A of theopposite body part. A loose connection may be achieved in this manner.The parts 286A are secured together by the compression nuts 285A whichsimultaneously secure the mount 267A to the pole 3. The projections 288Aof only one of the parts 286A can be seen in FIG. 38A, the other bodypart having projections in registration with the bottom four openings280A of the body part on which the projections 288A can be seen. Theprojections 288A and openings 280A are capable of receiving bolts (notshown) or the like through the mounting formations 279A for mountingitems on the modular mount 267A.

A modular mount 267B of a fourth embodiment shown in FIG. 38B is ofsimilar construction to the modular mount 267A of the third embodiment.Corresponding parts of the modular mount 267B will be indicated by thesame reference numbers as for 267A, but with the suffix “B”. The modularmount 267B comprises a tubular body 277B having two parts 286B and286B′. Unlike the parts 286A of the third embodiment, the parts 286B and286B′ are not identical. Instead, the part 286B′ has a socket member294B which is like the socket member 341 described hereinafter inrelation to FIGS. 52 and 53.

The fifth embodiment of the mount is shown in FIG. 38C and designatedgenerally at 267C. The modular mount 267C is of similar construction tothe modular mount 267B of the fourth embodiment. Corresponding parts ofthe modular mount 267C will be indicated by the same reference numbersas for 267B, but with the suffix “C”. The modular mount 267C differsfrom the mount 267B in that in place of the socket member 294B, a levelvial holder 13C is formed on part 286C′ of the modular mount. It will beunderstood that various forms of mounts or other structures may beformed on modular mounts (not shown) without departing from the scope ofthe present invention.

Some uses of these modular mounts are shown in FIGS. 40 and 41. In FIG.40, the fixed mount 201 attaches the bipod support 1, the single legsupport 221 and a data collector 289 at the same level. Moreover, abattery pack 290 is mounted on the positionable mount 267. Batteries 292held in the pack 290 are shown exploded from the pack in FIG. 40. Thearticles are exemplary only, as other articles could be mounted in asimilar fashion. The level 13 is shown mounted on the surveying pole 3independently of the modular mounts 201, 267. However, as shown in FIG.41, a modified level 13A can be constructed for tongue in grooveconnection to the mounting formation 279A of the modified positionablemount 267A. A walkie talkie 291 can be attached by tongue in grooveconnection to the mounting formation 279A on the opposite side.Meanwhile, the data collector 289 and a battery pack 290 can be boltedto the mount 267A. In this case, the battery pack 290 includes anattachment member 293 formed with internally threaded holes (not shown)which threadably receive the ends of the bolts 295 passing through anattachment member 297 of the data collector. Thus, it may be seen thatup to four items can be mounted at the same height on the surveying pole3 with the embodiments of the modular mounts 201, 267, 267A illustrated.

An adjustable support for a data collector case is shown in FIGS. 42-44to comprise an attachment member 299 attached by bolts 301 (FIG. 43) tothe fixed mount 201. A cylinder 303 projects outwardly from theattachment member 299 and receives a sleeve 305 of a bracket (generallyindicated at 307) thereon. The bracket further includes a channel 309having an open upper end and a closed lower end (FIG. 44) for receivinga slide 311 attached to a data collector case 313 through the open endinto the channel to connect the case to the bracket 307. The cylinder303 has a relatively large diameter in relation to its length, forexample the length of the cylinder may be 1½ inches and its diameter 17/16 inches. It is noted that the length of the body 269 of the fixedmount 201 helps to distribute loads over the larger surface area of thelower pole section 7.

The position of the bracket 307 about the axis of the cylinder 303 canbe changed by turning the bracket on the cylinder. To secure the bracket307 in selected angular position, first sets of detents 315 are providedon the ends of the sleeve 305 and a second set of detents 317 isprovided on the attachment member 299 extending circumferentially aroundthe cylinder 303. A cap screw 319 may thread into a central threadedopening 321 of the cylinder 303 and be screwed into the cylinder. Aflat, smooth underside of the head of the cap screw 319 engages one edgeof the sleeve 305 and forces it against the attachment member 299. Thedetents of one of the first sets of detents 315 engage with the secondset of detents 317 on the attachment member 299 to lock the bracket 307in a fixed angular position. Unscrewing the cap screw 319 releases thefirst and second sets of detents 315, 317 from meshing, allowing theangle of the bracket 307 to be changed. By providing a first set ofdetents 315 on both ends of the sleeve, the bracket 307 can be placed onthe cylinder 303 in either direction and still be capable of locking inselected angular positions.

A modified form of the attachment member and cylinder 303A are shown inFIGS. 45 and 46. The attachment member has the form of an elastic clip299A which can snap onto a modified fixed mount 201A in acircumferential channel 275 separating mounting formations 203A on eachside into two parts. The clip 299A allows for more rapid attachment (anddisconnection) of the cylinder 303A. Thus, the cylinder may be readilymoved from one side of the fixed mount 201A to the other.

A connection system of the present invention is shown in FIGS. 47-51.The system includes a first connector 325 which is fixed to an article(e.g., a walkie talkie). The article is not shown in FIG. 47 forclarity. A second connector is not shown in FIGS. 47-51 but can be ofthe same general construction as the bracket 307 in as much as thebracket includes a channel having a floor, side walls and inwardlyturned lips extending toward each other over the floor. A thirdconnector 327 (FIG. 47) has a back 329 and a generally U-shaped receiver331 having an open upper end. The third connector 327 may be attached toan object other than the surveying pole 3 such as a bag, another pieceof equipment or an piece of clothing (not shown). The first connector325 includes two connector components, a circular undercut slider 333and a rectangular undercut slider 335 aligned so a longitudinal axis ofthe rectangular slider passes through the center of the circular slider.These components are shown in hidden lines in FIG. 47 because they areon the opposite side of the first connector 325. The diameter of thecircular slider 333 is about the same as the width of the rectangularslider 335. When attached to the second connector (e.g., bracket 307),both the circular slider 333 and rectangular slider 335 are received inthe channel (e.g., channel 309) with their undercut portions capturingthe lips of the channel. To attach the first connector 325 to the thirdconnector 327, the first and third connectors are turned so that thecircular slider 333 is lined up with the open upper end of the U-shapedreceiver 331 and the rectangular slider 335 is positioned to one side ofthe U-shaped receiver. The first connector 325 may then be moved so thatthe circular slider 333 only is received in the U-shaped receiver 331.The first connector 325 may then be rotated so that the rectangularslider 335 moves to a position under the U-shaped receiver. Thisconfiguration is illustrated in FIGS. 48 and 49. Modified forms of thethird connector 327A, 327B are shown in FIGS. 50 and 51. A back 329A ofthe receiver 327A does not extend across the “U” in the version shown inFIG. 50. Slots 337 on either side of the U-shaped receiver 327B canreceive, for instance a belt (not shown) worn by a person. Thus, anarticle can be removed from the bracket 307 on the surveying pole 3 andattached to the belt quickly and easily.

A modified form of connecting an article such as the data collector case313 to the modified mount 201A is shown in FIGS. 52 and 53. The modifiedversion includes a socket member 341 extending outwardly from anattachment member 343 (of substantially the same construction as theattachment member 299). The socket member 341 includes a central hole345 and multiple locator holes 347 extending in a circle around thecentral hole. The central hole 345 can receive a peg 349 attached to a Cclamp holder 351 capable of gripping the case 313. The peg 349 has acircumferential groove 353 near its distal end which receives the end(not shown) of a hold pin 355 inside the socket member 341 to preventinadvertent withdrawal of the peg from the socket member. A small stud(not shown) on the side of the C clamp holder 351 is selectivelyreceived in one of the locator holes 347 around the central hole 345.The angular position of the C clamp holder 351 and the case 313 isselected by choosing the locator hole 347 into which the stud isinserted. A further modified version of the socket member 341A andattachment member is shown in FIG. 54. As with the version shown inFIGS. 45 and 46, the attachment member 343 is replaced by an elasticclip 343A for snap on connection to the fixed mount 201A.

Referring now to FIGS. 55-63, a foot assembly of a second embodiment isdesignated generally at 356, and shown mounted on the lower end of thesecond leg section 25. The foot assembly 356 includes a receptacle 360for receiving a lower end of the second leg section 25 onto a boss 365at the bottom of the receptacle (FIG. 57) to orient and locate the footassembly relative to the second leg section. Pan head screws 358 arereceived through respective openings 359 to secure the foot assembly 356to the second leg section 25. A foot pad 361 formed as one piece withthe receptacle 360 is used to apply foot pressure to drive the footassembly into the ground. Two generally triangular webs 363 locatedunder the foot pad 361 are arranged perpendicularly to each other in a“T” pattern. The webs 363 strengthen the foot pad 361 and providestability as will be described.

The foot pad 361 has a counterbore 362 extending through it whichreceives a screw 357 used to secure the foot assembly 356 (and hence thesupport) to the ground. The foot assembly 356 is able to engage avariety of terrain surfaces of different densities. These commonlyencountered terrain surfaces include concrete, asphalt, frozen ground,ice, loose soil, mud and sand. Stability of the survey support system isbest achieved by a positive connection of the support with all of thesevarying terrains. More particularly, the foot assembly 356 shouldconnectively resist several forces including upward/extraction of thefoot and also side-to-side rolling (pivoting about the axis of thesecond leg section 25). The greatest force to resist is found incompression and tension along the centerline of the leg. Differingdensities of the variously engaged terrains necessitate significantlydiffering sized bearing surface areas to attain the same degree ofstability. The present invention provides penetration and sufficientbearing on all these surfaces. For instance, on asphalt or ice,sufficient bearing surface is provided solely by the screw'spenetration, because a positive (threaded) connection with thosesurfaces can be made. However, on loose soil or sand where no positiveconnection can be made by the screw 357, a much larger bearing surfaceis provided by the webs 363 and underside of the foot pad 361.

Screw 357 may be a standard manufacture, metal screw-type masonryfastening anchoring product that is commercially available and istypically used to attach objects to masonry and concrete substrates. Asuitable example of these fasteners is produced by Illinois Tool Works,Inc. of Glenview, Ill. and is marketed under the mark “TAPCON”. In thecase of survey supports, some terrain surfaces that are encountered areparticularly hard and abrasive. The screw 357 still provides anadvantage even though it may not make a threaded engagement with thesurface. The screw is hardened and exceptionally resistant to wear.However, should wear ultimately occur, the exposed length of screw 357below the foot may be advanced to accommodate some abrasive wear. Sincethe screw 357 is of standard manufacture and is widely available, fieldreplacement of the screw itself is also possible. In fact, screws of thesame type and diameter, but of different lengths are also available andtherefore allow further adaptation of the support to specific fieldconditions.

Field adjustment of the exposed length of screw 357 (i.e., the length ofthe screw projecting below the bottom of the foot assembly 356, seeFIGS. 57 and 59) is anticipated. To provide for unobstructed adjustment,counterbore 362 is sized to receive screw 357 and a screwdriver (notshown) to allow for adjustment. A smooth upper portion 364 of thecounterbore 362 receives the head of the screw 357 below an uppersurface of the foot pad 361 and allows selective adjustment of thescrew. The lower portion of the counterbore 362 threadably engages thefoot assembly 356 so that rotation of the screw 357 produces extensionfrom or retraction into the counterbore. A washer 366 formed integrallywith the screw 357 at the based of the screw head is sized to closelyfit within counterbore 362 while still allowing movement of the screwwithin the counterbore. The close fitting relationship between the screwwasher 366 and counterbore 362 forms a seal and prevents dirt and debrisfrom entering a spaced between the underside of the washer 366 and thebottom of the smooth upper portion 364. Thus, dirt and debris will notlimit the amount of adjustment of the screw 357 which can be made.

Screw 357 may be used in several different ways to secure the foot tothe underlying ground or other surface. In the instances of use on hard,but rough terrain surfaces and when the support is used only to assistthe user in steadying the support, only the point of the screw isrequired to contact the terrain surface. The point is sharp and opposesthe compressive forces on the leg of the support. In other instances ofuse on moderately hard terrain surfaces such as frozen soil, asphaltpavement and ice, the screw 357 can be selectively extended to increasethe depth of penetration into the surface. The greater extension of thescrew 357 to provide a greater depth of terrain surface penetration isillustrated in FIG. 59 and FIG. 60. The foot assembly 356 is thrust intothe terrain by the user's foot pressure applied by stepping on the footpad 361 so that not only the exposed portion of the screw 357 penetratesthe surface, but at least a portion of the webs 363. In this use, thethreads of screw 357 are thrust into the terrain without rotation andcontact the terrain to provide a barbed, resistive connection in thesedense surfaces. Further stability is offered by the flat web surfaces371. These surfaces offer resistance to forces tending to unseat thefoot because of the orientation of the webs 363 and the surface areasavailable to distribute the loads applied through the legs 19, 21. Theorientation of the webs 363 relative to the remainder of the leg 19 willprovide surface areas which are not parallel to the applied loads. Withthe resulting increase in area for absorption of the applied loads,significant resistance to the forces tending to move the foot isgenerated.

When the support is used on hard terrain surfaces and is exposed to windor other destabilizing forces, another method of use is possible. Themethod in such case requires the creation of a hole in the hard terrainsubstrate surface as illustrated in FIG. 62. In this method, screw 357is first retracted fully into the foot 356. A pilot hole 370 is drilledinto a concrete or masonry substrate having size approximately equal tothe minor diameter of the screw 357 and depth sufficient to accommodatethe fully extended length of the screw. The foot assembly 356 is alignedover the hole 370 and the screw 357 is rotationally advanced into thehole (FIG. 62). The threads of the screw 357 directly engage theconcrete or masonry substrate in the hole 370. The screw 357 is advancedby rotation so that the washer 366 formed as one piece with the head ofthe screw (at its base) engages the bottom of the smooth portion 364.Further advancement of the screw 357 pulls the foot assembly 356downwardly against the substrate (e.g., the concrete surface illustratedin FIG. 62). When screw 357 is fully advanced, the threads of screw 357connectively engage both the substrate hole surface 370 and also thesurfaces of counterbore 362, thus forming a positive connection of thesupport to the concrete. While surveyors and other users of geomaticsupports normally do not install concrete screws, they do typicallyposses and use hole generating tools such as star-drills or cordlesshammer drills to produce holes in concrete surfaces for the mounting ofsurvey monuments, pins and markers. Additionally, these same users alsotypically possess screwdriver tools of the same type as required toengage screw 357. These same hole-generating capabilities andscrewdrivers thus may be conveniently utilized and applied to providereceptacle holes and to engage screw 357 in the above described manner.

Use of the support in less dense terrain surfaces such as soil, sand andmud are also anticipated. In instances of engaging less dense terrainsurfaces such as soil or sand, screw 357 alone does not providesufficient connective resistance required for stability on the support.To provide sufficient connective resistance on these less densesurfaces, the webs 363 of the foot 357 are also provided. In use, thesewebs 363 are downwardly thrust into the substrate terrain tosubstantially their full height. To facilitate downward penetration inthe terrain, these webs 363 are formed in a cross shape in order toprovide a small cross-sectional surface. Terrain penetration is furtherfacilitated by foot pad 361 wherein the user applies his or her weightto insert the foot 356 into the terrain. The broad surfaces of the webs363 however are arranged to provide bearing surfaces which areperpendicular to each other to enhance resistance to the forces of theleg in maintaining stability of the support.

Insertion of the foot into less dense terrain can be difficult for theuser as the foot can tend to rotate in response to uneven resistance inthe substrate terrain. For instance, one side of the foot can encountera small rock while the other encounters only soil. Rotation of the foot(about the axis 367 of the leg 25) is undesirable, as the webs must befully planted in order to provide optimum stability resistance toforces. To resist this rotational effect, several features are combined.For one, the foot pad 361 is formed in a shape that is wider than thedistance from the foot pad 361 to the line of contact with the terrain(e.g., the width of the foot pad is greater that the height from thefoot pad to the distal surface 371 of the webs 363). The contact area ofthe foot pad 361 encountered by the users shoe tends to cause the webs363 to remain perpendicularly aligned during insertion. Further, theflat surfaced sides of webs 363 tend to guide insertion once theypenetrate the terrain. An additional feature is the contact line 371formed at the distal ends of the webs. The width of the contact linetends to further distribute and balance the forces of insertion of thewebs 363 as they penetrate the terrain. The contact line 371 tries toengage the ground over its whole length tending to cause the foot tosquare up before penetrating the ground.

When used on hard terrain surfaces such as concrete, instability of thesupport can also occur if the legs 25 rotate about their centerlines. Inthese conditions, the hard terrain surface tends to allow only a pointcontact of the foot. This rotation can occur due to an offset of thepoint of contact of the foot to the terrain in relationship to thecenterline of the leg. The foot assembly 356 of the present invention isformed so that its point of contact with the underlying surface iscoplanar with the centerline 367 of the leg to reduce the tendency ofthe foot assembly 356 to rotate as it is being forced into the ground.However, the foot assembly 356 is also constructed so that the foot pad361 and webs 363 are not coaxial with and are arranged at an angle tothe centerline 367 to resist compressive and extensive forces applied bythe second leg section 25 to the foot assembly.

When introducing elements of the present invention or the preferredembodiment(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

1. A support system for supporting a geomatic pole, the support systemcomprising first, second and third legs each having mounting structurefor connection to the geomatic pole, the first and second legs beingcapable of connection to the geomatic pole independently of the thirdleg for two point support of the geomatic pole, and the third leg beingcapable of connection to the geomatic pole with the first and secondlegs for three point support of the geomatic pole, wherein: the mountingstructure comprises: a first head element mounting the first and secondlegs and constructed for releasable connection to a geomatic pole at afirst location; and a second head element mounting the third leg andconstructed for releasable connection to a geomatic pole at a secondlocation spaced apart from the first location; and the angle between thefirst and second legs is greater than 90° and less than 120°.
 2. Asupport system as set forth in claim 1 wherein the angle between thefirst and second legs is greater than 95° and less than 110°.
 3. Asupport system as set forth in claim 2 wherein the angle between thefirst and second legs is about 105°.
 4. A support system as set forth inclaim 1 wherein the first and second head elements each include achannel for slidingly receiving a portion of the geomatic pole thereinto connect the first and second head elements to the geomatic pole.
 5. Asupport system as set forth in claim 4 wherein each of the first andsecond head elements further comprises a retainer movable to close therespective channel for use in retaining said geomatic pole portion inthe channel.
 6. A support system as set forth in claim 5 wherein eachchannel comprises an open end for receiving said geomatic pole portioninto the channel and a closed end, and wherein each retainer comprises agate movable relative to the respective head element to selectivelyblock the open end of the channel.
 7. A support system as set forth inclaim 1 further comprising a mount adapted for connection to thegeomatic pole, the mount being capable of attaching the first, secondand third legs thereto.
 8. A support system as set forth in claim 7wherein the mount comprises tongue in groove connector elements, thefirst head element and the second head element having second tongue ingroove connector elements adapted to connect to the first tongue ingroove connector elements.
 9. A support system as set forth in claim 8wherein the first tongue in groove connector elements each comprise anundercut formation and each of the second tongue in groove connectorelements comprises a channel sized for slidingly receiving the undercutformation.
 10. A support system as set forth in claim 7 in combinationwith the geomatic pole.
 11. A support system as set forth in claim 1wherein the first and second legs are mounted on the first head elementfor pivoting inwardly and outwardly with respect to the first headelement and the third leg is mounted on the second head element forpivoting inwardly and outwardly with respect to the second head element.12. A support system for supporting a geomatic pole, the support systemcomprising a head including a first head element and a second headelement, first and second legs mounted on the first head element, thefirst head element being formed for releasable connection to thegeomatic pole for two point support of the geomatic pole, a third legmounted on the second head element, the second head element being formedfor releasable connection separately from the connection of the firsthead element for use in conjunction with said first and second legs andfirst head element for three point support of the geomatic pole, whereinthe angle between the first and second legs is greater than 90° and lessthan 120°.
 13. A support system as set forth in claim 12 wherein theangle between the first and second legs is greater than 95° and lessthan 110°.
 14. A support system as set forth in claim 13 wherein theangle between the first and second legs is about 105°.
 15. A supportsystem as set forth in claim 12 wherein the first and second headelements each include a channel for slidingly receiving a portion of thegeomatic pole therein to connect the first and second head elements tothe geomatic pole.
 16. A support system as set forth in claim 15 whereineach of the first and second head elements further comprises a retainermovable to close the respective channel for use in retaining saidgeomatic pole portion in the channel.
 17. A support system as set forthin claim 16 wherein each channel comprises an open end for receivingsaid geomatic pole portion into the channel and a closed end, andwherein each retainer comprises a gate movable relative to therespective head element to selectively block the open end of thechannel.
 18. A support system as set forth in claim 1 in combinationwith the geomatic pole, the geomatic pole including a mount adapted forconnecting the first head element and the second head element to thegeomatic pole.
 19. The combination as set forth in claim 18 wherein themount comprises tongue in groove connector elements, the first headelement and the second head element leg having second tongue in grooveconnector elements adapted to connect to the first tongue in grooveconnector elements.
 20. The combination as set forth in claim 19 whereinthe first tongue in groove connector elements each comprise an undercutformation and each of the second tongue in groove connector elementscomprises a channel sized for slidingly receiving the undercutformation.
 21. The combination as set forth in claim 18 wherein each ofsaid first, second and third legs comprises first and second sections,the first and second sections being telescopingly interconnected forextension and retraction relative to the second section to selectivelylengthen or shorten the leg.
 22. The combination as set forth in claim21 wherein the geomatic pole further comprises a leg holder forreceiving lower ends of the first, second and third legs to hold thelegs in a stowed position, the leg holder being mounted on the geomaticpole above a lower end of the pole whereby the legs are retracted in thestowed position held by the leg holder to provide an unobstructed lineof sight to the lower end of the geomatic pole.
 23. A support system asset forth in claim 12 wherein the first and second legs are mounted onthe first head element for pivoting inwardly and outwardly with respectto the first head element and the third leg is mounted on the secondhead element for pivoting inwardly and outwardly with respect to thesecond head element.
 24. A support system as set forth in claim 12further comprising a hinge for each of said first, second and third legsadapted to connect the leg to the head for pivoting movement of the leg,and a hinge lock for each leg adapted to lock the leg in a fixedposition of pivoting relative to the head.
 25. A support system as setforth in claim 12 wherein each leg comprises first and second sections,the first and second sections being telescopingly interconnected forextension and retraction of the first section relative to the secondsection to selectively lengthen or shorten the leg, and a releasablelocking device for locking the first and second sections of the leg in aselected position of extension.